New York ? One key lesson if you want to be on Donald Trump’s payroll: Don’t let the boss fly off unnoticed.

The Donald chose software executive Kelly Perdew, 37, to join his staff during the season finale of “The Apprentice” on Thursday. He rejected feisty lawyer Jennifer Massey despite her bare-knuckled fight for the job.

Massey’s fatal mistake on the reality show’s final challenge may have been not escorting Trump to a VIP reception. Instead, he walked to a helicopter and flew off.

Given the choice of a job in Las Vegas or New York, Perdew chose to help Trump on his massive development on Manhattan’s West Side.

Massey, 30, a Princeton and Harvard Law School graduate, attacked like a pit bull in the boardroom, even accusing Perdew of behind-the-scenes backstabbing. Her confrontational style eventually turned off Trump.

“Your teammates did not really like you too much and you did lose too much,” Trump said in “firing” Massey.

The two candidates were put through one last nerve-jangling competition: seeing who could manage a charity event more efficiently. Massey organized a basketball game involving NBA stars, while Perdew ran a polo match in leafy Connecticut.